Motorola ASTRO SPECTRA Service Manual

February 3, 2003 6881076C20-E
9-10 Basic Troubleshooting: Receiver Troubleshooting
No Receiver
Audio or
Receive Does
Not Unsquelch
Audio PA Circuit 1. Check codeplug to ensure correct frequency
and signaling (PL, DPL) is enabled (use the
appropriate radio programming software).
2. Check continuity of F500 on command board.
If open, check for speaker leads shorted to
ground. Replace, if necessary.
Regulators (Command
Board)
Check for 9.6 Vdc on pin 10 of J500 and +5V on
pin 1 of J500.
If not there, then check for A+ at pin 30 of P502
and SWB+ at pin 31 of P502.
If OK, replace the command board.
RF Board Replace RF board.
VOCON Board Replace VOCON board.
Audio
Distorted or
Not Loud
Enough
Codeplug Is the codeplug properly configured including
bandwidth and signaling?
VOCON Board Is there >100 mVrms audio on pin 40 of P501?
If not, replace VOCON board.
Synthesizer Not On
Frequency/Working
Check synthesizer frequency across pins 14 and
16 of P503.
If off by more than 250Hz, then go to the
Synthesizer Troubleshooting Chart on
page 9-12.
Command Board Replace command board.
Table 9-6. Receiver Troubleshooting Chart (Continued)
Symptom Possible Cause
Correction or Test (Measurements Taken
at Room Temperature)

Motorola ASTRO SPECTRA Specifications

General

Frequency Range	136-174 MHz, 403-470 MHz
Number of Channels	Up to 255
Channel Spacing	12.5 kHz, 20 kHz, 25 kHz
Modulation	FM
Operating Temperature	-22°F to +140°F (-30°C to +60°C)